Batteries sometimes generate heat suddenly due to short circuits and so on. In this case, arrangement of a heat absorbing layer in part of a battery allows heat to be absorbed properly. Inorganic hydrates such as calcium sulfate dihydrate, and inorganic hydroxides such as aluminum hydroxide are known as materials constituting heat absorbing layers for batteries (Patent Literatures 1 and 2). Inorganic hydrates and inorganic hydroxides have large theoretical endotherm and are preferable for materials constituting heat absorbing layers for batteries.